"John, I often find your mastery of the profane polyphiloprogenitive." Sherlock steepled his fingers under his chin and rocked briefly onto the balls of his feet.
John scratched the back of his neck. "Uhm... Thanks?"
"Did you know you often swear in iambic pentameter? When one is not on the receiving end of one of your soliloquies, it's really rather mesmerizing. Brilliant even."
"Who are you, and what have you done with Sherlock?"
With a huff, Sherlock rolled his eyes. "And so much for brilliant."
"Oi! Don't be a bloody..." John caught himself. Sherlock cocked an eyebrow at his friend. "What's all this about?"
"It has come to my attention that while you are often complimentary of my work, frequently overly so, I seldom return the kindness." Sherlock shrugged and turned his face away.
John snickered and tried cover it with a cough. "You wanted to compliment me, and the best you could come up with is that my swearing is poetic?"
"Not just poetic. Polyphiloprogenitive." Sherlock ducked his head.
"What's it even mean?"
"Prolific. Very much so."
John snorted and laughed outright. "Oh God." The doctor shook his head and looked up at the consulting detective with a grin. "I think you might have a concussion. That... suspect," another pause from John, and another raised eyebrow from Sherlock, "got a few solid blows in to your head."
Sherlock hummed in consent. "You may be right. I'm not feeling quite myself."
"All right, let's get you home." John took Sherlock by the elbow and guided him to the street to hail a cab. "Idiot. " John chuckled. The corners of Sherlock's mouth quirked up into a slight smile, intended only for his friend.
"John?"
"Yeah, Sherlock?"
"I really do think you're brilliant. In your way."
"You know what? I'll take it. I think you're pretty polyphiloprogenitive yourself."
"Obviously."